Universal clamp with adjustable retention means

ABSTRACT

A manually operated toggle type clamp having an adjustable retention means suitable for stopping and holding the clamp arm in a predetermined open position. Optionally when setting up the clamp, adjustable retention means is temporarily positioned for try-out and then welded or otherwise permanently secured for repeated use when the preferred final open position has been determined. In the preferred embodiment the adjustable retention means is substantially enclosed within the clamp mechanism.

Apr. 2, 1974 2,670,415 2/1954 Anderson et al. 2,744,552 5/1956 Novick............. 3,117,208 1/1964 Svensson............................. 3,311,367 3/1967 Scndoykas Primary ExaminerR0y Lake Assistant ExaminerNei1 Abrams Attorney, Agent, or FirmFarley, Forster & Farley [57] ABSTRACT A manually operated toggle type clamp having an adjustable retention means suitable for stopping and holding the clamp arm in a predetermined open position. Optionally when setting up the clamp, adjustable retention means is temporarily positioned for try-out and then welded or otherwise permanently secured for repeated use when the preferred final open position has been determined. In the preferred embodiment the adjustable retention means is substantially enclosed within the clamp mechanism.

16 Claims, 5 Drawing Figures 19%, ll/l/A. 4 L

RETENTION MEANS Inventors: Alexander W. McPherson,

Farmington; Jack J. Sendoykas, St. Clair Shores, both of Mich.

Assignee: Dover Corporation (De-Sta-Co Division), Detriot, Mich.

Filed: Jan. 31, 1972 Appl. No.: 222,106

Field of Search... 74/97, 520, 527; 200/67 AA, 172 B; 269/201, 228, 285, 321

Reierences Cited UNITED STATES PATENTS 11/1925 Nelson..,.......,.......... 12/1937 Gardner..........................

United States Patent McPherson et al.

[ 1 UNIVERSAL CLAMP WITH ADJUSTABLE PATENTEBAPR 219M] SHEET 1 BF 2 FIG.5

UNIVERSAL CLAMP WITH ADJUSTABLE RETENTION MEANS BACKGROUND OF THE INVENTION Prior art manual clamps of the type disclosed comprise a clamping arm pivoted on a base with a toggle mechanism actuated by a handle to swing the clamping arm into and out of clamping position. When the clamp is released, the handle and toggle mechanism swing the clamping arm out of the way of the work piece where with exterior mountings the weight of the handle and clamp arm may retain the clamp in the fully open position. In order to more positively retain the clamp in open position with any mounting position, prior art clamps have utilized a retainer attached to the base on the outside of the clamping mechanism. However, they have not provided the advantages of the present retainer with regard to flexibility in adjustment of open ing, retaining force, consistency of action, durability, internal location and freedom from malfunction.

SUMMARY OF THE INVENTION The present invention provides an adjustable retention means which is located substantially inside the toggle and handle linkage of the clamp. A collar having two protrusions is adjusted simply by means of a set screw to any position desired within the range of the clamp arm movement. One of the protrusions engages a rotatable ball contained within a spring loaded socket which in turn is retained within another link of the clamp mechanism. The other protrusion directly engages the other member of the clamp mechanism to provide a final stop and in combination with the engagement of the first protrusion provides a stop and hold function developed by the geometric positioning of the parts when the second protrusion is engaged. Once the preferred position for stopping and holding the handle has been determined, the collar may be welded or otherwise permanently secured in final position for repeated use. The clamp may be located in any position relative to vertical operation of gravity with assurance that when the handle is pulled and the clamp opened, the clamp and handle will remain in the final open position desired.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a side view of a clamp in closed position with the fully open position shown in dashed outline;

FIG. 2 is an end view of the clamp in closed position;

FIG. 3 is a partially sectioned side view of the clamp showing the open position in full line with the stop and hold initially engaged;

FIG. 4 is an enlarged fragmentary sectional view of the retention means shown in FIG. 3 illustrating the geometric configuration which creates the retention forces necessary to positively retain the clamp; and,

FIG. 5 is a cut-away of an alternate stop and hold.

DESCRIPTION OF THE PREFERRED EMBODIMENT With reference to FIGS. 1 and 2, the clamp includes two parallel side plates and a central clamping arm 12 pivotally attached at 14 between the side plates. The clamping arm 12 has a clamping extention 16 welded in any desired position on the nose 18 of the clamping arm. The side plates 10 are likewise suitably welded in any desired pivotal position to a central support 11 adapting it to the specific use to which the clamp will be put. A handle link generally denoted by 20 includes a yoke 22 which straddles the side plates 10 and is pivotally joined to the side plates by a pivot bolt 21 and nut 23. The yoke 22 is connected to an extension 24 of the handle 26, welded at 28 in any desired position.

Within the yoke 22 in the plane of side plates 10 are a pair of toggle links 30 which are pivotally attached to the yoke 22 by a cross pin 32. The cross pin 32 is permanently secured to move integrally with the pair of toggle links 30. The toggle links 30 are also pivotally attached by a cross pin 34 to the clamping arm 12. As shown in FIG. 3, the extension 24 of the handle 26 includes a bore hole 36 having a counter bore 38 intersecting the inner surface 40 located between the arms 22. Pressed into the bore 36 and counterbore 38, is a shouldered sleeve 42 having a bore hole 44 threaded at the outer end. The sleeve 42 includes a partial ball socket 46 engaging a substantially ball shaped member 48. The ball shaped member 48 also engages a partial socket 50 located in aslidable member 52 which in turn engages the cylindrical side wall 43 of the inner portion of the bore hole 44. The slidable member 52 is adjustably pre-loaded by the Allen head screw 54 which engages the threads of borehole .44 and compresses Belleville washers 56, located inside the bore hole 44. I

The inner member 52 includes a central pin shaped extension 58 which extends through the Belleville washers 56 and screw 54. Turning of the screw 54, therefore will adjust the preload of the ball 48 in the socket portions 46 and 50. Mounted on the pin 32 between the links 30 is a collar 60 which includes a set screw 62 located in a threaded bore hole 64 and engageable with the pin 32. The collar 60 includes a positive stop 66 shown engaged with the inner surface 40 in FIG. 3. Press fit into a bore hole 68 in the collar 60 is a cylindrical pin 70 having a hemispherical end 72. The end 72 as shown in FIG. 3, engages a partial toroidal surface 74 formed on one side of the ball 48.

The pin 32 is constrained to rotate with the links 30,

as indicated by the splined engagement 76, in FIG. 2. The stop and hold position may be temporarily set by tightening the set screw 62 against the pivot pin 32 with the stop 66 engaged and handle 26 in the open position preferred. Thus, the position of the collar 60 on the pin 32 can be adjusted for try-out purposes when installing the clamp. When the permanent preferred position has been determined, the collar is welded to the links 30 to prevent any loosening under repeated use.

With the stop portion 66 of the collar engaged against the inside surface 40, the retention in the open position is provided by the final geometrical positioning of the hemispherically ended pin 70 and ball 48. In FIG. 4, the stop and hold is shown in final engaged position, illustrating a suitable geometry for desired reten tion torque required to rotate the collar counterclockwise relative to the sleeve 42, this torque being resisted by the force exerted by the ball 48 upon the pin 70 and their geometric relation. As shown relative to thecenter 80, the center 76 of the hemispherical surface 72 lies angularly clockwise past a line 78 drawn between the center 80 of the collar 60 and the center 82 of the ball 48. While the force of the ball 48 against the cylinder 70 is maximum when the three centers 76, 80 and 82 are aligned on the line 78, the increasing lever arm provides for a restraining clockwise torque increasing to a maximum in a direction clockwise beyond the line 78. As a final result a snap action retention is created with the stop 66 preventing movement of the collar 60 clockwise beyond the maximum retention torque posi tion.

The hemispherical end 72 isfully seated into the toroidal surface 74 before the forces developed by the snap action loading are applied. Point contact under load is thus prevented and full contact developed before the load is applied thereby reducing wear of the engaging surfaces.

In FIG. an alternate form of the stop and hold provides an additional resiliently loaded member to provide'rotational limits for the movement of the ball. A modified ball 148 includes a conical depression 84 adapted to engage the hemispherical end 88 of a 'pin 86, The pin 86 is contained within a bore hole 90 inside the modified pin shaped extension 158 of the inner member 152 and communicating with the partial socket 150. The pin 86 is resiliently urged against the conical depression'84 by the spring 92 also located within the bore hole 90. The pin 86 thus prevents the ball 148 from turning beyond the position necessary for proper initial engagement with the pin 170.

We claim:

l. A clamp movable between closed and open positions including a clamp element and inter-connected toggle pivoted elements having one extremity of angular relationship establishing a locked clamping position and another extremity of angular relationship reached at a predeterminable final open position, and means for retaining said clamp in said final open position characterized by a rotatable member mounted on one of said inter-connected pivoted elements, a mating member on another of said inter-connected pivoted elements, a mating member on another of said inter-connected pivoted elements, means for establishing a pressurized mutual engagement of said members in said final open position, said rotatable member and mating member engaging with a substantial extent of contact during the establishment of said pressurized engagement contact prior to the application of the maximum retention force therebetween.

2. The clamp of claim 1 including means for adjustably determining the final open position.

3. The clamp of claim 2 includingmeans for permanently securing said adjustable means after initial tryout to secure the operative relative position of said retention means for the desired final open position.-

4. The clamp of claim 1 including resilient means to provide predetermined maximum retention force.

5..The clamp of claim 4 including adjustable means to vary the effective resilient pressure.

6. The clamp of claim 1 wherein the clamp includes a toggle link and a handle link with said rotatable memberon said handle link and mating member on said toggle link.

7. The clamp of claim 6 wherein the mating member includes a collar pivotally attached to the toggle link for adjustably determining the final open position.

8. The clamp of claim 7 wherein said collar includes a stop member adapted to stop further opening motion of said clamp upon engagement with said handle link.

9. The clamp of claim 6 wherein said mating member rotates said rotatable member sufficiently to allow application of the maximum retention force therebetween prior to said final open position.

10. The clamp of claim 7 including adjustable resilient means to apply the retention force to said rotatable member and thereby resist reverse disengagement rotation of said rotatable member.

11. The clamp of claim 10 including a resiliently urged protrusion in said handle link engageable with said rotatable member and adapted to control the angular rotation of said rotatable member.

12. The clamp of claim 10 wherein said retention means includes a socket and said rotatable member comprises a ball in said socket having an annular depression formed to engage said mating member.

13. The clamp of claim 12 wherein said resilient means includes Belleville washers and compression adjustment means for said washers adapted to apply an adjustable preload compressive force to said socket and ball thereby providing an adjustable resistance to rotation of said ball.

14. A clamp comprising a base, a handle link pivotally attached to said base, a clamping arm pivotally attached to said base, a toggle link pivotally attached to saidclamping arm, said toggle link having a second pivotal attachment to said handle link to provide a toggle locking action in clamped position, and characterized by a collar on said second pivotal attachment constrained to rotate with second toggle link, a first protrusion onsaid collar, a member rotatably attached to said handly link, said rotatable member adapted to engage said first protrusion upon opening of said clamp and to resist a reserve disengagement rotation, a second protrusion on said collar adapted to stop further opening motion of said clamp upon engagement with said handle link, said two protrusions being so related that reverse rotation resistance of said rotatable member is applied against said first protrusion when said second protrusion is engaged thereby providing an overcenter retaining action to the final open position of said clamp.

15. The clamp of claim 14 including adjustable resilient means adapted to adjust the reverse resistance of said rotatable member.

16. The clamp of claim 14 including a resiliently urged protrusion in said handle link engageable with said rotatable member and adapted. to control the angular rotation of said rotatable member. 

1. A clamp movable between closed and open positions including a clamp element and inter-connected toggle pivoted elements having one extremity of angular relationship establishing a locked clamping position and another extremity of angular relationship reached at a predeterminable final open position, and means for retaining said clamp in said final open position characterized by a rotatable member mounted on one of said inter-connected pivoted elements, a mating member on another of said inter-connected pivoted elements, a mating member on another of said interconnected pivoted elements, means for establishing a pressurized mutual engagement of said members in said final open position, said rotatable member and mating member engaging with a substantial extent of contact during the establishment of said pressurized engagement contact prior to the application of the maximum retention force therebetween.
 2. The clamp of claim 1 including means for adjustably determining the final open position.
 3. The clamp of claim 2 including means for permanently securing said adjustable means after initial try-out to secure the operative relative position of said retention means for the desired final open position.
 4. The clamp of claim 1 including resilient means to provide predetermined maximum retention force.
 5. The clamp of claim 4 including adjustable means to vary the effective resilient pressure.
 6. The clamp of claim 1 wherein the clamp includes a toggle link and a handle link with said rotatable member on said handle link and mating member on said toggle link.
 7. The clamp of claim 6 wherein the mating member includes a collar pivotally attached to the toggle link for adjustably determining the final open position.
 8. The clamp of claim 7 wherein said collar includes a stop member adapted to stop further opening motion of said clamp upon engagement with said handle link.
 9. The clamp of claim 6 wherein said mating member rotates said rotatable member sufficiently to allow application of the maximum retention force therebetween prior to said final open position.
 10. The clamp of claim 7 including adjustable resilient means to apply the retention force to said rotatable member and thereby resist reverse disengagement rotation of said rotatable member.
 11. The clamp of claim 10 including a resiliently urged protrusion in said handle link engageable with said rotatable member and adapted to control the angular rotation of said rotatable member.
 12. The clamp of claim 10 wherein said retention means includes a socket and said rotatable member comprises a ball in said socket having an annular depression formed to engage said mating member.
 13. The clamp of claim 12 wherein said resilient means includes Belleville washers and compression adjustment means for said washers adapted to apply an adjustable preload compressive forcE to said socket and ball thereby providing an adjustable resistance to rotation of said ball.
 14. A clamp comprising a base, a handle link pivotally attached to said base, a clamping arm pivotally attached to said base, a toggle link pivotally attached to said clamping arm, said toggle link having a second pivotal attachment to said handle link to provide a toggle locking action in clamped position, and characterized by a collar on said second pivotal attachment constrained to rotate with second toggle link, a first protrusion on said collar, a member rotatably attached to said handly link, said rotatable member adapted to engage said first protrusion upon opening of said clamp and to resist a reserve disengagement rotation, a second protrusion on said collar adapted to stop further opening motion of said clamp upon engagement with said handle link, said two protrusions being so related that reverse rotation resistance of said rotatable member is applied against said first protrusion when said second protrusion is engaged thereby providing an overcenter retaining action to the final open position of said clamp.
 15. The clamp of claim 14 including adjustable resilient means adapted to adjust the reverse resistance of said rotatable member.
 16. The clamp of claim 14 including a resiliently urged protrusion in said handle link engageable with said rotatable member and adapted to control the angular rotation of said rotatable member. 